Voters cast ballots in Denver during the 2008 election. Colorado's unaffiliated voters are ballooning, while the parties struggle to keep pace.

WASHINGTON — Colorado continues to add hundreds of thousands of unaffiliated voters — while both Republican, and especially Democrat, voter registrations are not keeping pace, according to a study released today.

Colorado, considered a pivotal swing state this fall, has gained almost half a million independent voters just since the 2008 elections, according to a study by Third Way, a left-leaning DC-based think tank.

Third Way analyzed voter registration numbers from 2008 through May 1, 2012. Colorado mirrored trends in seven other swing states that show gigantic gains in unaffiliated independent voters and drops in party registrations both on the Democrat and Republican side, according to the study.

Since 2008, Colorado has added voters in all groups becauses the state’s population is growing. But Democrats have added the fewest voters at 13,497, according to the study. Republicans have added 36,896 voters since 2008. There are more than 130,000 more independent voters now in Colorado compared to 2008, according to the study.

“The ranks of Independents have swelled by nearly half a million,” Third Way said, in a statement. “To win in November, both campaigns will need to woo these voters.”

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Debbie Bosanek, center, Warren Buffett's secretary, at President Barack Obama's 2012 State of the Union address.

Democrats this week will be pushing their tax fairness argument in advance of the Senate taking up a bill that would implement the so-called Buffett Rule.

The President is planning a Tuesday trip to Florida to make this case for the Buffett Rule, which under the bill to be considered by the Senate, would require people who earn more than $2 million to pay at least a 30 percent tax rate. It is based on reports that billionaire Warren Buffett has a lower tax rate than his secretary. You should expect coordinated events in other key states, including Colorado.

“Making sure that everyone plays by the same set of rules is key to ensuring the economic security of the middle class, and the president will continue to make this case next week,” Amy Brundage, a White House spokeswoman, told the New York Times.

While that might resonate with partisans, a new poll by a nonpartisan think tank suggests that a key block of swing-state independent voters is more interested in polices that attempt to provide opportunity rather than focusing on income inequality.

Colorado Republicans have registered 6,000 more voters than the Democrats in 2012.

WASHINGTON — Colorado Republicans have registered almost 6,000 more voters than Democrats since the beginning of 2012 — including almost 2,000 new voters in March alone.

GOP leaders say the successful numbers are in part thanks to high gas prices and an aggressive grassroots effort to get people registered. Volunteers have canvassed neighborhoods and county fairs.

“Voter registration numbers show that either Obama’s organization isn’t performing as planned, or more likely, Coloradans know they can’t afford four more years of President Obama,” said the Colorado GOP Chairman Ryan Call, in a statement.

Sen. Mark Udall would like Congress to mix it up and Republicans and Democrats sit together during the Jan. 24 State of the Union address, but it's unclear whether there is an appetite this year for that kind of love.

WASHINGTON — Reaction was mixed Thursday to Democrat Sen. Mark Udall’s pitch to again sit in mixed company, Republicans and Democrats, during the Jan. 24 State of the Union address.

Udall will promote the idea spearheaded by left-leaning think tank Third Way, which sent a letter to GOP House Speaker John Boehner and Democrat Senate Majority Leader Harry Reid urging a 24-hour “knock it off” period before the address as well as members to pick someone from the other party to sit next to the night of the president’s speech.

“The speech is not for the folks in the hall, it’s for millions of folks watching at home,” said Sean Gibbons at Third Way. “Plenty go through their daily lives where they disagree with people, but they probably break bread with family members, neighbors who disagree with them. You’d think it would be easy for members of Congress to do it in one night.”

Joey Bunch has been a reporter for 28 years, including the last 12 at The Denver Post. For various newspapers he has covered the environment, water issues, politics, civil rights, sports and the casino industry.